package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 * 服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
@Slf4j
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    // 这种方法不推荐，会出现循环依赖
//    private IVoucherOrderService proxy;
//    @Autowired
//    public void setProxy(IVoucherOrderService proxy) {
//        this.proxy = proxy;
//    }
    @Resource
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;

    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    // 异步处理线程池
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    @PostConstruct
    private void Init() {
        SECKILL_ORDER_EXECUTOR.submit(new VocherOrderHandler());
    }

    /**
     * 秒杀优惠券下单 - stream 消息队列
     */
    private class VocherOrderHandler implements Runnable {
        String queueName = "stream.orders";
        @Override
        public void run() {
            while (true) {
                try {
                    // 1. 获取消息队列中的订单信息 XREADGROUP GROUP g1 c1
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    // 2. 判断消息是否获取成功
                    if (list == null || list.isEmpty()) {
                        // 2.1 如果失败，说明没有消息，进行下一次循环
                        continue;
                    }
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    // 3. 如果成功可以下单
                    handleVoucherOrder(voucherOrder);
                    // 4. ACK 确认 SACK stream.order g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("take error", e);
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while (true) {
                try {
                    // 1. 获取 pending-list 中的订单信息 XREADGROUP GROUP g1 c1
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    // 2. 判断消息是否获取成功
                    if (list == null || list.isEmpty()) {
                        // 2.1 如果失败，说明 pending-list 没有消息，进行下一次循环
                        break;
                    }
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    // 3. 如果成功可以下单
                    handleVoucherOrder(voucherOrder);
                    // 4. ACK 确认 SACK stream.order g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("take error", e);
                }
            }
        }
    }

    // 秒杀优惠券下单 阻塞队列方案
//    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
//    private class VocherOrderHandler implements Runnable {
//        @Override
//        public void run() {
//            while (true) {
//                try {
//                    // 1. 获取队列中的订单信息
//                    VoucherOrder voucherOrder = orderTasks.take();
//                    // 2. 创建订单
//                    handleVoucherOrder(voucherOrder);
//                } catch (InterruptedException e) {
//                    log.error("take error", e);
//                }
//            }
//        }
//    }

    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        Long userId = voucherOrder.getUserId();
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        boolean isLock = lock.tryLock();
        if (!isLock) {
            log.error("不允许重复下单！");
            return;
        }
        try {
            proxy.createVoucherOrder(voucherOrder);
        } finally {
            // 释放锁
            lock.unlock();
        }
    }

    private IVoucherOrderService proxy;
    /**
     * 秒杀优惠券下单 阻塞队列方案
     *
     * @param voucherId 优惠券ID
     * @return
     */
    @Override
    // 这里不能有Translational 因为注解的默认传播模式是REQUIRED
    public Result seckillVoucher(Long voucherId) {
        Long userId = UserHolder.getUser().getId();
        // 订单ID
        long orderId = redisIdWorker.nextId("order");
        // 1. 执行Lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString(),
                String.valueOf(orderId)
        );
        int r = result.intValue();
        if (r != 0) {
            // 0: 成功 1: 库存不足 2: 订单重复
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        return Result.ok(orderId);
    }
    /**
     * 秒杀优惠券下单 阻塞队列方案
     *
     * @param voucherId 优惠券ID
     * @return
     */
//    @Override
//    // 这里不能有Translational 因为注解的默认传播模式是REQUIRED
//    public Result seckillVoucher(Long voucherId) {
//        Long userId = UserHolder.getUser().getId();
//        // 1. 执行Lua脚本
//        Long result = stringRedisTemplate.execute(
//                SECKILL_SCRIPT,
//                Collections.emptyList(),
//                voucherId.toString(),
//                userId.toString()
//        );
//        int r = result.intValue();
//        if (r != 0) {
//            // 0: 成功 1: 库存不足 2: 订单重复
//            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
//        }
//        // 为0 有购买资格， 把下单信息保存到阻塞队列
//        VoucherOrder voucherOrder = new VoucherOrder();
//        // 订单ID
//        long orderId = redisIdWorker.nextId("order");
//        voucherOrder.setId(orderId);
//        voucherOrder.setUserId(userId);
//        voucherOrder.setVoucherId(voucherId);
//        // 放入阻塞队列
//        orderTasks.add(voucherOrder);
//        // 获取代理对象
//        proxy = (IVoucherOrderService) AopContext.currentProxy();
//        return Result.ok(orderId);
//    }

//    /**
//     * 秒杀优惠券下单 乐观锁方案
//     * @param voucherId
//     * @return
//     */
//    @Override
//    // 这里不能有Translational 因为注解的默认传播模式是REQUIRED
//    public Result seckillVoucher(Long voucherId) {
//        // 1. 查询优惠券
//        SeckillVoucher seckillVoucher = seckillVoucherService.getById(voucherId);
//        // 2. 判断秒杀是否开始
//        if (seckillVoucher.getBeginTime().isAfter(LocalDateTime.now())) {
//            return Result.fail("秒杀尚未开始");
//        }
//        // 3. 判断秒杀是否结束
//        if (seckillVoucher.getEndTime().isBefore(LocalDateTime.now())) {
//            return Result.fail("秒杀已结束");
//        }
//        // 4. 判断库存是否足够
//        if (seckillVoucher.getStock() < 1) {
//            return Result.fail("库存不足");
//        }
//        Long userId = UserHolder.getUser().getId();
//        // SimpleRedisLock lock = new SimpleRedisLock(stringRedisTemplate, "order:" + userId);
//        RLock lock = redissonClient.getLock("lock:order:" + userId);
//        boolean isLock = lock.tryLock();
//        if (!isLock) {
//            return Result.fail("不允许重复下单");
//        }
//        try {
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//            return proxy.createVoucherOrder(voucherId);
//        } finally {
//            // 释放锁
//            lock.unlock();
//        }
//
//    }

    /**
     * 创建订单
     *
     * @param voucherOrder 优惠券订单
     * @return 订单ID
     */
    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        // 5. 一人一单逻辑
        Long userId = voucherOrder.getUserId();
        Long voucherId = voucherOrder.getVoucherId();
        int count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
        if (count > 0) {
            return;
        }
        // 6. 扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1")
                .eq("voucher_id", voucherId)
                .gt("stock", 0) // 减库存之前判断库存是否充足
                .update();
        if (!success) {
            return;
        }
        // 7. 订单
        save(voucherOrder);
    }
    /**
     * 秒杀优惠券下单 悲观锁方案
     * @param voucherId
     * @return
     */
//    @Override
//    @Transactional
//    public Result seckillVoucher(Long voucherId) {
//        // 1. 查询优惠券
//        SeckillVoucher seckillVoucher = seckillVoucherService.query()
//                .eq("voucher_id", voucherId)
//                .last("for update")
//                .one();
//        // 2. 判断秒杀是否开始
//        if (seckillVoucher.getBeginTime().isAfter(LocalDateTime.now())) {
//            return Result.fail("秒杀尚未开始");
//        }
//        // 3. 判断秒杀是否结束
//        if (seckillVoucher.getEndTime().isBefore(LocalDateTime.now())) {
//            return Result.fail("秒杀已结束");
//        }
//        // 4. 判断库存是否足够
//        if (seckillVoucher.getStock() < 1) {
//            return Result.fail("库存不足");
//        }
//        // 5. 扣减库存
//        boolean success = seckillVoucherService.update()
//                .setSql("stock = stock - 1")
//                .eq("voucher_id", voucherId)
//                .eq("stock", seckillVoucher.getStock())
//                .update();
//        if (!success) {
//            return Result.fail("库存不足");
//        }
//        // 6. 创建订单
//        VoucherOrder voucherOrder = new VoucherOrder();
//        long orderId = redisIdWorker.nextId("order");
//        voucherOrder.setId(orderId);
//        Long userId = UserHolder.getUser().getId();
//        voucherOrder.setUserId(userId);
//        voucherOrder.setVoucherId(voucherId);
//        save(voucherOrder);
//        return Result.ok(orderId);
//    }
}
